Method for integrated treatment of red mud
SUBSTANCE: method includes magnetic-gravitational treatment of red mud. The starting red mud first undergoes dispergation in the presence of sodium hexametaphosphate in a rotary-pulsation apparatus, followed by low-gradient wet magnetic separation in a field with strength of 0.1-0.15 T to obtain a magnetite and a bulk concentrate, subjecting the bulk concentrate to high-gradient magnetic separation in two steps in a field with a strength of not less than 1.2 T to extract magnetic and nonmagnetic fractions, subjecting the magnetic fraction to gravitational concentration on a concentration table to obtain a hematite concentrate and tailings, combining the nonmagnetic fraction with the tailings from gravitational concentration and performing two-step selective flocculation in the presence of a flocculant to separate a component which primarily consists of aluminium and silicon oxides from an iron-containing product, which is concentrated by high-gradient magnetic separation with field strength of 0.5-0.7 T to obtain an additional iron-containing product, which is combined with the hematite concentrate to obtain an iron-containing concentrate, and residual aluminosilicates which are combined with the component primarily consisting of aluminium and silicon oxides to obtain an aluminosilicate product.
EFFECT: high degree of extraction of iron into an iron-containing product and obtaining an aluminosilicate product with high iron content.
The invention relates to the field of metallurgy and can be used in the processing of red mud is a waste alumina production - for iron concentrate and aluminosilicate product that can be used for the manufacture of construction materials.
There is a method of processing red mud from alumina production, including the production of a slurry of red mud, the classification of the pulp, class of particles of 40-60 microns for the Department alumosilicates fraction with a particle size of more than 40-60 μm and high-gradient magnetic separation of particles less than 40-60 μm at pH slurry of 1.5 to 4 and a magnetic field strength of 30 to 80 kA/m (0,4-1,0 T) getting rich scandium-containing magnetic concentrate (output 4-7%, Fe2O3- 65-76%) (USSR author's certificate 1715874, IPC C22B 59/00, C01F 7/02, op. 29.02.1992).
The disadvantage of this method is not a high yield of the resulting iron-containing product, due to the fact that part of the iron remains in the particles larger than 40-60 μm, which are alumosilicate faction.
The known method for integrated processing of red mud, including the filing of the red sludge in the form of a pulp with an alkaline medium, magnetic sedimentation separator separating ferromagnetic components (iron is the first product from the pulp, activation of the pulp and electrophoretic separation for separation of negatively charged particles, mainly consisting of silicon dioxide, and positively charged particles, the bulk of which are oxides of aluminum and titanium, with the last translation in the pulp and subsequent electrophoretic separation of particles of oxides of aluminum and titanium (RF patent 2198943, IPC C22B 7/00, 34/00, op. 20.02.2003).
The disadvantage of this invention is not a high quality iron product and the complexity of the method, providing for two-phase electrophoretic separation.
There is a method of enrichment of old tailings tailings, including their processing with the release of iron minerals, with old tailings for processing serves as a pulp, and processing is carried out by protective screening pulp, its classification according to the class of 0.16 μm, a primary and a cleaner cell magnetic separation with grain size less than of 0.16 μm, dehydration of the products obtained, both magnetic separation of lead in an inhomogeneous magnetic field with induction of 0.4 T, and the slurry in a magnetic field serves at a rate of 0.2-0.3 m/s the resulting concentrate contains 66% iron, and the tails from both separators contain 10-12% iron and after dehydration is used for the production of building mater what Alov (patent of Ukraine # 26931, IPC B03C 1/00, B03B 7/00, op. 29.12.1999).
The disadvantage of this method is not a high yield of the resulting iron-containing product, due to the fact that part of the iron remains in the particles more of 0.16 μm, representing the tails of separation.
A method of obtaining marketable products from red mud by magnetic gravity separation adopted for the prototype, including the classification of the original sludge granulometric composition of obtaining clay fraction and sand, high-gradient magnetic separation of sand separating the magnetic iron concentrate) and nonmagnetic fractions, followed by gravity separation of non-magnetic fractions in a centrifugal field or concentration table with getting heavy fraction, representing compounds of iron, zircon, rutile and gold, and light fraction containing silicates. The collective output of the iron concentrate is 15-18%, the content of Fetotal- 51% (Bragin YU.N., Dobrovolskaya TI, Borisov V.V. and other New technology of producing marketable products from red mud. "The state of problems and directions for use in the national economy red mud". Collection of scientific papers, Nikolaev, 1998, p.23-30).
The disadvantages of this method are not a high yield of iron in the concentrate due to C who lnym allocation of iron, contained in the magnetite and silicate refractory mineral formations, in the magnetic product with separation and heavy fraction of the gravitational enrichment, and obtaining as a light fraction product requiring processing for future use.
The technical result of the invention is to increase the output of iron ore concentrate with a high content of iron and getting aluminosilicate product suitable for further use.
This result is achieved in that in the method for integrated processing of red mud containing hematite, chamosite, goethite, magnetite, silicates, by means of magneto-gravity processing of obtaining iron concentrate and alumina products, according to the invention of the original red mud previously subjected to dispersion in the presence of sodium hexametaphosphate in a rotary pulsation apparatus, followed by discordantly wet magnetic separation field strength of 0.1-0.15 Tesla obtaining magnetite and collective concentrate bulk concentrate is subjected to high-gradient magnetic separation in two stages in the field of not less than 1.2 TL with removing the magnetic and nonmagnetic fractions, magnetic fraction is subjected to gravity is the enrichment in the concentration table with getting hematite concentrate and tailings, and the non-magnetic fraction unite with tails gravity concentration and subjected to two-stage selective flocculation in the presence of flocculant to separate component, consisting mainly of oxides of aluminum and silicon from iron-containing product, which enrich the high-gradient magnetic separation at a field strength of 0.5-0.7 T with additional iron-containing product, the latter combined with the hematite concentrate to produce iron concentrate and residual silicates, which unite with the component, consisting mainly of oxides of aluminum and silicon with getting aluminosilicate product. This discordantly wet magnetic separation is carried out at a ratio W:T=3÷4:1, the sodium hexametaphosphate is used in the amount of 100-200 g/t tails gravity separation prior to selective flocculation is subjected to screening to a particle size of minus 0,032 mm, and as a flocculant use hydrolyzed polyacrylamide in the amount of 3-5 g/so
The proposed set of operations of the proposed method is aimed at increasing output of iron ore concentrate and the maximum extraction of iron from red mud that has a complex structure with a large number of mineral phases in the concentrate:
- dispersion make in rotary-pulsation is the first device in the presence of sodium hexametaphosphate - for disaggregation of flocs, which included grains of iron-containing minerals, and removal of oxide films;
- niskogradnja wet magnetic separation to highlight Selfnominated minerals (magnetite);
- two-stage wet high gradient magnetic separation for separation of weakly magnetic minerals hematite, chamosite, goethite, and increase the output of iron-containing product;
- gravitational enrichment to a concentration buffet magnetic fraction allocated to the second stage separation, for separation of hematite from chamosite;
- screening of non-magnetic product class to 0.032 mm;
- dispersion make undersize product screen size minus 0,032 mm;
selective flocculation of two-phase dispersed non-magnetic component obtained in the second stage high-gradient magnetic separation, is designed for flocculation of finely disperse silica and silicates, followed by the separation of the oxides of aluminum and silicon from iron-bearing minerals at concentrations of iron oxides and increased output of iron ore concentrate;
wet magnetic separation in a high magnetic field for additional allocations flokulirovannym iron minerals.
Preliminary dispersion make the original red mud in the presence of sodium hexametaphosphate in the count is the number of 100-200 g/t provides a disaggregation of flocs which included grains of iron-containing minerals, reduced reagent consumption, affects the dispersion make slimes, and increased consumption does not improve dispersion and is impractical.
The magnetic field strength of 0.1-0.15 Tesla when carrying out the separation of dispersed sludge allows not only to highlight the magnetite, but also creates conditions for more efficient magnetic separation in a strong field with a strength of not less than 1.2 to 1.4 T with separation of weakly magnetic fraction (hematite product).
The selective flocculation in the presence of flocculant - hydrolyzed polyacrylamide, taken in an amount of 3-5 g/t, provides optimum flocculation of minerals.
Removing sfokusirovannykh iron-bearing minerals at a field strength of 0.5-0.7 T allows you to extract iron in additional iron-containing product, increases the extraction of iron from red mud, and also provides a receiving aluminosilicate product with low content of iron.
Thus, the claimed method provides integrated waste in the production of alumina - red-sludge - to produce high-quality iron-containing aluminosilicate products suitable for further use.
The method is as follows.
Original red the sludge (Fe 30-35%, size 80% CL - 5.0 µm) is subjected to dispersion with sodium hexametaphosphate (GMF-100-200 g/t) in the rotary pulsation apparatus for disaggregation of flocs and removal of oxide film, followed by discordantly magnetic separation field strength of 0.1-0.15 T magnetic separator PBM emitting in sinnamahoning fraction of magnetite concentrate (Fe 52,7-53,0%) and in the non-magnetic fraction of the bulk concentrate. The bulk concentrate is subjected to high-gradient magnetic separation field intensity higher than the 1.2 TL (optimally a 1.4 Tesla) magnetic separator "Humboldt" in two stages with obtaining magnetic fraction (Fe - 41,5%output % 23,5%) and non-magnetic fractions, representing mainly the oxides of aluminium, silicon and iron (Fe and 29.6%, output fraction - 76,5%). The magnetic fraction is subjected to gravitational enrichment to a concentration table HOLMAN obtaining hematite concentrate (Fe - 48,1%, the yield of the concentrate 15%) and tails (Fe - 35,8%, exit - 22%). Tails gravity separation combined with non-magnetic fraction obtained in the second stage high-gradient magnetic separation, and subjected to two-stage selective flocculation with the introduction of hydrolyzed polyacrylamide (SDS page - 3-5 g/t) in free-flow cyclone for separating light faction the component, consisting mainly of oxides of aluminum and silicon (Fe - 14,3%, the yield of fraction 20%), from iron-containing product (Fe - 30,9%, exit - 70%). Iron-containing product is enriched high-gradient magnetic separation at a field strength of 0.5-0.7 T magnetic separator "Humboldt" to retrieve sfokusirovannykh iron-bearing minerals with additional iron-containing product (Fe - 52,0%, output - 24%) and residual silicates (Fe - 20.9%, exit - 46%).
Additional iron-containing product combined with the hematite concentrate to produce iron concentrate (Fe - 50%, exit - 35%), which after filtering and drying, can be used in ferrous metallurgy.
Residual silicates combined with the component, which is the light fraction selective flocculation, obtaining aluminosilicate product (Fe - 22,3%, output - 65%), which can be used in the construction industry.
For an additional increase in the extraction of iron tails gravity separation prior to selective flocculation is subjected to screening to a particle size of minus 0,032 mm, and discordantly wet magnetic separation is carried out at a ratio W:T=3÷4:1.
The claimed method is tested in laboratory conditions. From red mud, sod is rzasa, %: Fe2O3of 45.4; A2O3- 13,8; SiO2- 10,10; CaO - 6,4 received iron-containing concentrate composition, %: Fetotal- 50,0; FeO - 10,8; Fe2O3- 53,1; And2About3- 11,4; SiO2- 7.62mm; CaO - 1,36, and aluminosilicate product composition, %: Fe - 22,3; FeO - 3,12; Fe2O3- 28,4; And2About3- 16,9; SiO2- 13,2; Cao - 12,6.
Output of iron ore concentrate, 35%, iron extraction - 54,7%.
1. Method for integrated processing of red mud containing hematite, chamosite, goethite, magnetite and silicates, by means of magneto-gravity processing of obtaining iron concentrate and alumina products, characterized in that the original red mud previously subjected to dispersion in the presence of sodium hexametaphosphate in a rotary pulsation apparatus, and then carry out discordantly wet magnetic separation field strength of 0.1-0.15 Tesla obtaining magnetite and collective concentrate bulk concentrate is subjected to high-gradient magnetic separation in two stages in the field of not less than 1.2 TL with removing the magnetic and nonmagnetic fractions, the magnetic fraction is subjected to gravitational enrichment to a concentration the table with the receipt of hematite concentrate and tailings, and the non-magnetic fraction combined with the tails of the gravitational abogada the Oia and subjected to two-stage selective flocculation in the presence of flocculant to separate component, consisting mainly of oxides of aluminum and silicon from iron-containing product, which enrich the high-gradient magnetic separation at a field strength of 0.5-0.7 T with additional iron-containing product, which combine with the hematite concentrate to produce iron concentrate and residual silicates, which unite with the component, consisting mainly of oxides of aluminum and silicon with getting aluminosilicate product.
2. The method according to claim 1, characterized in that discordantly wet magnetic separation is carried out at a ratio W:T=3÷4:1.
3. The method according to claim 1, characterized in that the sodium hexametaphosphate is used in the amount of 100-200 g/so
4. The method according to claim 1, characterized in that the tails of gravity separation prior to selective flocculation is subjected to screening to a particle size of minus 0,032 mm
5. The method according to claim 1, characterized in that as a flocculant use hydrolyzed polyacrylamide in the amount of 3-5 g/T.
SUBSTANCE: solid copper-vanadium wastes are leached with water to obtain copper-vanadium pulp, to which is added calcium hypochloride or clarified pulp from gas treatment facilities from titanium-magnesium production with concentration of active chlorine equal to 15-90 g/dm3, with ratio of calcium hypochlorite to the copper-vanadium pulp of (1.5-2.0):1. The pulp is held while stirring for 2-5 hours. Hydrochloric acid is added while stirring until achieving solution pH of 2.0-3.0. The suspension is filtered and the copper (II) solution is fed into a cementing apparatus. The precipitate in the form of a mixture of a reducing agent and copper powder is separated into copper powder and a reducing agent. The copper powder is washed, filtered and dried and iron impurities are removed by magnetic separation. After decantation, the reducing agent is returned to the cementing step.
EFFECT: high copper extraction and improved processing properties of the obtained copper powder.
10 cl, 3 ex
SUBSTANCE: invention relates to extraction of metals from flow rich in hydrocarbons and carbon residues with the help of treatment section. Proposed method comprises feeding of said flow to extraction by its mixing with appropriate hydrophilising agent to kill hydrophobic properties of said flow. Mix of said flow and said agent are fed so separation of liquid phase containing major portion of hydrophilising agent and hydrocarbons precipitated from solid phase. Separated solid phase is dried at 350°C to remove medium-light hydrocarbon components. Separated solid phase, preferably dried, is fed for leaching by alkaline solution in the presence of air and/or oxygen, possibly, in the presence of emulsifier or its precursor. Then, leached mix is fed for separation to remove solid residue from leach liquor.
EFFECT: higher yield of valuable metals and hydrocarbons.
13 cl, 3 dwg, 1 tbl, 8 ex
SUBSTANCE: method includes oxidising roasting, percolation leaching of the roasted product with aqueous solution of an oxidising agent or mixtures of oxidising agents to obtain a rhenium-containing solution and an insoluble residue, sorption of rhenium from the rhenium-containing solution in a separate apparatus, drying the insoluble residue, mixing with fluxing agents and fusion on a metal collector. Percolation leaching is carried out at redox potential values of 900-1100 mV and temperature of 50-90°C, with simultaneous sorption of rhenium, followed by desorption and separation of rhenium compounds or rhenium metal from the strippant. The fluxing agents used to fuse the insoluble residue are fluorspar, sodium carbonate and sodium nitrate. Fusion is carried out at temperature of 1200-1800°C on a metal collector in several steps, while discharging the formed slag after each step and fusing the next portion of the mixture on the collector from the previous fusion with separation of the alloy of platinum metals with the collector.
EFFECT: high degree of extraction of rhenium, low reactant consumption, labour input, faster processing of the material, considerable reduction of the volume of solutions which require recycling.
8 cl, 1 dwg, 1 ex
SUBSTANCE: device contains successively installed a feed hopper, an open hearth furnace, an afterburning chamber, a recuperator of combustion air heating, a heat recovery unit, a smoke exhauster and a smokestack, means for fuel supply. The furnace is provided with a bag filter for purification of flue gases from dust and a catalytic apparatus for purification of flue gases from carbon oxides and nitrogen oxides. The catalytic apparatus consists of a vertical case with a conic bottom, inside which from top to bottom placed are: a vertical heat-exchanger, a liquid distributer, an absorption section, a desorption-cooling section, an aspiration hood with a fan and a Venturi tube. A method includes preparation of a charge in the form of a mixture of wastes with flux, loading of the charge and its melting in a bath of the open hearth furnace at a temperature of 1450-1500°C. Performed are: discharge of released combustible components into the afterburning chamber with heat recovery of flue gases, purification of flue gases from dust in the bag filter, purification of smoke gases from carbon oxides and nitrogen oxides is performed in the catalytic apparatus.
EFFECT: method improvement.
2 cl, 2 dwg
SUBSTANCE: group of inventions relates to utilisation of solid mercury-containing wastes, in particular fluorescent lamps. A method of utilisation of solid mercury-containing wastes includes an oxidation stage with further stand, processing a wastes mixture with a demercurised solution of an alkali metal polysulfide with further stand of the reaction mixture. Wastes are divided into two parts. One part, which contains crushed wastes, is processed with an oxidant, and then with a demercurised iodine-alcohol solution or a sodium sulfide solution. The second part of wastes in the form of aeromixture is passed through a nanoporous carbon sorbent NCMS-J. A device for utilisation of mercury-containing wastes contains a unit of loading and crushing, a purification unit and an aeromixture unit. The purification unit is made in the form of a truncated cone, connected by means of a flange to a cylindrical reservoir with a perforated screw, provided with a valve for the solution discharge, and an upper part of the perforated screw is provided with an unloading flange for discharge into a storage hopper. The aeromixture unit is made in the form of a column type adsorber with the nanoporous carbon sorbent NCMS-J.
EFFECT: ensuring reduction of mercury vapour concentration in air and water extract to TLV level, neutralisation of solid wastes of compact fluorescent lamps to IV class of hazard.
7 cl, 1 dwg, 4 ex
SUBSTANCE: furnace includes a housing formed with refractory external side, front and rear end walls, two baths restricted with bottoms, an arch and walls, two drain tap holes, a gas duct and a pedestal, on which all parts are arranged. In the furnace there is external heat insulation of walls, which consists of asbestos tailings and a double layer of asbestos boards. The furnace pedestal has two layers made of light-weight brick with the double layer of asbestos boards between them, a quartz sand layer from below and from above, which is mixed with asbestos tailings, and three layers of asbestos boards on the top, on which bottom block are laid. A casting shoe includes a housing formed with refractory external side, front and rear end walls, a bath, restricted with a bottom, an arch and walls, and drain tap holes. The casting shoe pedestal has two layers made of light-weight brick and separated with an asbestos board layer, and a lower asbestos board layer. The casting shoe has two tap holes made in quick-changeable tap-hole bricks in a box. The furnace has two turning chutes with a turning bowl, which are installed on brackets welded to the casting shoe box, which are turned during liquid metal pouring process for subsequent pouring of molten metal in the furnace to pouring equipment located in a maintenance sector with an angle of 143°. Five injection burners are installed in the furnace and the casting shoe. The furnace operates at natural and artificial draft with a dust and gas cleaning system.
EFFECT: improving efficiency and decreasing heat losses.
5 cl, 12 dwg
SUBSTANCE: electronic waste is crushed on a hammer crusher; crushed copper is added, and then, it is fused in presence of flux during 45-60 minutes at the temperature of 1320-1350°C with air blowdown at its flow rate of 3-4.5 l/h and the obtained slag containing at least 2.6 wt % of precious metals is separated from slag.
EFFECT: effective electronic waste processing with increase of content of precious metals in an alloy.
SUBSTANCE: mixture, consisting of sulphur powder, granules of floatation sulphur pyrite of grade KSF-4 in mixture with broken stone with fraction 20-70 mm or brick crumbs, which are simultaneously agent binding mercury in ionised and neutral forms, taken in ratio 1:9 by weight, and water. After that, mixture is homogenised at rotation rate 20 rev/min, argon is supplied at rate 5.5-6.5 m3/h and then mercury-containing wastes are charged in amount which is at least 50 times less than weight of sulphur powder. Grinding of wastes is carried out to complete binding of metal mercury into water-insoluble compound HgS.
EFFECT: simplification of technology, increase of ecological safety of the process.
SUBSTANCE: method includes combined grinding of wastes with sulphur powder and crushing medium in rotary reactor for binding metal mercury into water-insoluble compound. As crushing medium used is sulphur pyrate with fraction 50-150 mm, which is simultaneously agent, binding mercury in ionised and neutral forms. Before combined grinding mixture of sulphur powder, sulphur pyrate and water is preliminarily homogenised, and reactor is filled with nitrogen, supplied at rate 7.5-8.5 m3/h, in amount which is at least 50 times less than weight of sulphur powder. After that mercury-containing wastes are charged and grinding is carried out to complete binding of metal mercury into water-insoluble compound HgS.
EFFECT: simplification of technology and increase of processing process safety.
SUBSTANCE: oxidised zinc-containing materials with coke dross as a hard carbon reducer are supplied into a rotary tubular furnace and exposed to Waelz process with supply of blow in the form of a steam and air mixture into zone of temperatures 1050-1150°C with content of steam in the mixture 14-25%.
EFFECT: reduced consumption of a reducer and content of zinc and lead in a clinker, eliminates softening of material in a furnace.
2 tbl, 2 ex
FIELD: non-iron metallurgy, in particular reprocessing of aluminum waste.
SUBSTANCE: claimed method includes junk charge into premelted flux at ratio of 1:(5-10); heating up to melt temperature; smelting under flux layer, and separation of metal from flux. Equimolar mixture of sodium chloride and potassium chloride with addition of 2.9-52.6 % (in respect to total flux weight) magnesium fluoride is used as flux, and in melting process flux layer with thickness of 4.5-20 cm is maintained. Method affords the ability to conserve original composition and eliminate additional burdening with magnesium.
EFFECT: decreased burn-off loss, especially for magnesium, metal of improved quality.
4 cl, 3 tbl, 5 ex
FIELD: non-iron metallurgy, in particular reprocessing of lead cakes from zinc manufacturing.
SUBSTANCE: claimed method includes heat treatment of lead cake with flux followed by smelting wherein before heat treatment mixture of lead cake, calcium hydroxide, and clinker from lead cake milling is balled to produce pellets. Pellets have fineness preferably of 30-100 mm. Method of present invention affords the ability to increase total coefficient of lead recovery by 3.1 %.
EFFECT: decreased energy consumption and reduced dust content in exhaust gas.
2 cl, 1 tbl
FIELD: noble metal hydrometallurgy.
SUBSTANCE: invention relates to method for acid leaching of platinum method from secondary raw materials, in particular from ceramic support coated with platinum metal film. Target metals are leached with mixture of hydrochloric acid and alkali hypochlorite at mass ratio of OCl-/HCL = 0.22-0.25 and redox potential of 1350-1420 mV.
EFFECT: decreased leaching temperature, reduced cost, improved platinum metal yield.
FIELD: sludge recovery from surface depositions of chemical equipment.
SUBSTANCE: invention relates to method for recovery of sludge containing platinum-group metals from equipment using platinum metal-based catalysts. Method includes treatment with aqueous solution of active chemical agent (e.g. sodium-ammonium-substituted ethylenediaminetetraacetic salts) while controlling pH value and removing sludge retained on treated surface with diluted aqueous solution of mineral salts or mixture thereof. pH value is adjusted at 2-10, preferably at 3-9 by adding of organic acid selected from group containing citric, oxalic, maleic, phthalic, adipic, glutaric, succinic acids or basic agents selected from sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate, and hydrochloric acid, sulfuric acid or phosphoric acid is used as mineral acid.
EFFECT: recovery platinum-group metal with improved yield.
4 cl, 1 tbl, 12 ex
FIELD: rare, dispersed and radioactive metal metallurgy, in particular hydrometallurgy.
SUBSTANCE: invention relates to method for reprocessing of polymetal, multicomponent, thorium-containing radwastes, formed when reprocessing of various mineral, containing rare-earth elements, Nb, Ta, To, V, Zr, Hf, W, U, etc. Method includes treatment of solution and/or slurry with alkaline agent; introducing of sulfate-containing inorganic compound solution and barium chloride; treatment of obtained hydrate-sulfate slurry with iron chloride-containing solution, and separation of radioactive precipitate from solution by filtration. As alkali agent magnesia milk containing 50-200 g/dm2 of MgO is used; treatment is carried out up to pH 8-10; sodium sulfate in amount of 6-9 g Na2SO4/dm2 is introduced as solution of sulfate-containing inorganic compound; barium chloride solution is introduced in slurry in amount of 1.5-3 g BaCl2/dm2. Hydrate-sulfate slurry is treated with solution and/or slurry containing 0.8-16 Fe3+/dm2 (as referred to startingsolution) of iron chloride, followed by treatment with high molecular flocculating agent and holding without agitation for 0.5-2 h. Radioactive precipitate is separated from mother liquor, washed with water in volume ratio of 0.5-2:1; then washed with sodium chloride-containing solution and/or slurry in volume ratio of 0.5-2:1; radioactive precipitate is removed from filter and mixed with mineral oxides in amount of 0.5-0.8 kg MgO to 1 kg of precipitate. Formed pasty composition is fed in forms and/or lingots and presses with simultaneous heating up to 80-1200C.
EFFECT: filtrate with reduced radioactivity due to increased codeposition coefficient of natural Th-232-group radioactive nuclide, in particular Ra-224 and Ra-228, with radioactive precipitates.
10 cl, 1 ex
FIELD: chemical technology; recovery of deactivated and decontaminated radioactive industrial wastes.
SUBSTANCE: proposed method that can be used for deactivating and decontaminating industrial radioactive wastes incorporating Tb-232 and their daughter decay products (Ra-228, Ra-224), as well as rare-earth elements, Fe, Cr, Mn, Sl, Ti, Zr, Nb, Ta, Ca, Mg, Na, K, and the like includes dissolution of wastes, treatment of solutions or pulps with barium chloride, sulfuric acid, and lime milk, and separation of sediment from solution. Lime milk treatment is conducted to pH = 9 - 10 in the amount of 120-150% of total content of metal oxyhydrates stoichiometrically required for precipitation, pulp is filtered, and barium chloride in the amount of 0.4 - 1.8 kg of BaCl2 per 1 kg of CaCl2 contained in source solution or in pulp, as well as pre-diluted sulfuric acid spent 5 - 20 times in chlorine compressors in the amount of 0.5 - 2.5 kg of H2SO4 per 1 kg of BaCl2 are introduced in filtrate. Alternately introduced in sulfate pulp formed in the process are lime milk to pH = 11 - 12, then acid chloride wash effluents from equipment and industrial flats at pulp-to-effluents ratio of 1 : (2 - 3) to pH = 6.5 - 8.5, and pulp obtained is filtered. Decontaminated solution is discharged to sewerage system and sediment of barium and calcium sulfates and iron oxysulfate are mixed up with oxyhydrate sediment formed in source pulp neutralization process; then 35 - 45 mass percent of inert filler, 10 - 20 mass percent of magnesium oxide, and 15 -m 25 mass percent of magnesium chloride are introduced in pasty mixture formed in the process while continuously stirring ingredients. Compound obtained is subjected to heat treatment at temperature of 80 - 120 oC and compressed by applying pressure of 60 to 80 at.
EFFECT: reduced radioactivity of filtrates upon separation of radioactive cakes due to enhanced coprecipitation of natural radionuclides.
7 c, 1 ex
FIELD: chemical technology; deactivation and decontamination of radioactive industrial products and/or wastes.
SUBSTANCE: proposed method designed for deactivation and decontamination of radioactive industrial products and/or production wastes incorporating Th-232 and its daughter decay products (Ra-228, Ra-224), as well as rare-earth elements, Fe, Cr, Mn, Al, Ti, Zr, Nb, Ta, Ca, Mg, Na, K, and the like and that ensures high degree of coprecipitation of natural radionuclides of filtrates, confining of radioactive metals, and their conversion to environmentally safe form (non-dusting water-insoluble solid state) includes dissolution of wastes, their treatment with barium chloride, sulfuric acid, and lime milk, and separation of sediment from solution. Lime milk treatment is conducted to pH = 9-10 in the amount of 120-150% of that stoichiometrically required for precipitation of total content of metal oxyhydrate; then pulp is filtered and barium chloride is injected in filtrate in the amount of 0.4 - 1.8 kg of BaCl2 per 1 kg of CaCl2 contained in source solution or in pulp and pre-dissolved in sulfuric acid of chlorine compressors spent 5-20 times in the amount of 0.5 - 2.5 kg of H2SO4 per 1 kg of BaCl2. Then lime milk is added up to pH = 11 - 12 and acid chloride wash effluents of equipment and production floors are alternately introduced in sulfate pulp formed in the process at pulp-to-effluents ratio of 1 : (2-3) to pH = 6.5 - 8.5. Filtrate pulp produced in this way is filtered, decontaminated solution is discharged to sewerage system, sediment of barium and calcium sulfates and iron oxysulfate are mixed up with oxyhydrate sediment formed in source pulp neutralization, inert filler and 0.5 - 2 parts by weight of calcium sulfate are introduced in pasty mixture while continuously stirring them. Compound obtained in the process is placed in molds, held therein at temperature of 20 - 50 oC for 12 - 36 h, and compacted in blocks whose surfaces are treated with water-repelling material.
EFFECT: reduced radioactivity of filtrates upon separation of radioactive cakes.
8 cl, 1 dwg, 1 ex
FIELD: utilization of secondary raw materials containing iron, zinc and lead, mainly wastes of steel-making process at control of basicity of Waelz process slag.
SUBSTANCE: proposed method includes mixing the charge containing raw materials and chemically active fine-grained carbon carrier, agglomeration and treatment of conglomerates thus obtained in furnace. Treatment is performed in rotary furnace working on counter-flow principle of charge and gas atmosphere; in the course of treatment, part of carbon carrier is fed to conglomerates so that total amount of carbon is lesser than 80% of amount of carbon required for reactions in charge; amount of chemically active fine-grained carbon carrier is strictly substoichiometric relative to all reactions in charge requiring carbon.
EFFECT: enhanced balance of energy of Waelz process; increased productivity; improved quality of wastes.
FIELD: production of aluminum by electrolysis of molten salts; processing wastes of this process.
SUBSTANCE: proposed method includes delivery of solid fluorocarbon-containing wastes and oxygen-containing gas into reactor followed by high-temperature roasting for obtaining secondary raw material for production of aluminum. Finely-dispersed fluorocarbon-containing and sulfur-containing wastes are fed for roasting at weight ratio of fluorine to sulfur no less than 4:1; anode gases of electrolytic aluminum production process taken from organized gas cleaning system are used as oxygen-containing gas. Wastes are delivered in form of suspension in which liquid-to-solid ratio is maintained at 0.5-1.5:1. Proposed method improves operation of electric precipitators and ensures return of compounds in form of secondary high-quality regenerating cryolite.
EFFECT: reduced emissions of toxic agents into atmosphere.
FIELD: waste treatment.
SUBSTANCE: multicomponent waste material is preliminarily impregnated with solution of salt of metal-collector in amount ensuring weight content of metal-collector in melt exceeding content of metallic components therein. Material is then calcined and melted in reductive atmosphere after addition of slag-forming flux based on metal fluorides. Melt is stirred and kept in liquid state over a period of time long enough to allow separation of slag and metallic phases. Resulting slag and metal are tapped and mechanically separated when solidified.
EFFECT: achieved high degree of recovering metals in collecting alloy at minimum expenses.